Measuring the outcomes and pharmacoeconomic consequences of venous thromboembolism prophylaxis in major orthopaedic surgery

Venous Thromboembolism Prophylaxis in Otolaryngologic Patients Using Caprini Assessment

OBJECTIVE

The aim was to determine the utilization of Caprini guideline-indicated venous thromboembolism (VTE) prophylaxis and impact on VTE and bleeding outcomes in otolaryngology (ORL) surgery patients.

METHODS

Elective ORL surgeries performed between 2016 and 2021 were retrospectively identified. Logistic regression models were used to examine the association between patient characteristics and receiving appropriate prophylaxis, inpatient, 30- and 90-day VTE and bleeding events.

RESULTS

A total of 4955 elective ORL surgeries were analyzed. Thirty percent of the inpatient cohort and 2% of the discharged cohort received appropriate risk-stratified VTE prophylaxis. In those who did not receive appropriate prophylaxis, overall inpatient VTE was 3.5-fold higher (0.73% vs. 0.20%, p = 0.015), and all PE occurred in this cohort (0.47% vs. 0.00%, p = 0.005). All 30- and 90-day discharged VTE events occurred in those not receiving appropriate prophylaxis. Inpatient, 30- and 90-day discharged bleeding rates were 2.10%, 0.13%, and 0.33%, respectively. Although inpatient bleeding was significantly higher in those receiving appropriate prophylaxis, all 30- and 90-day post-discharge bleeding events occurred in patients not receiving appropriate prophylaxis. On regression analysis, Caprini score was significantly positively associated with likelihood of receiving appropriate inpatient prophylaxis (odds ratio [OR] 1.05, confidence interval [CI] 1.03-1.07) but was negatively associated in the discharge cohort (OR 0.43, CI 0.36-0.51). Receipt of appropriate prophylaxis was associated with reduced odds of inpatient VTE (OR 0.24, CI 0.06-0.69), but not with risk of bleeding.

CONCLUSION

Although Caprini VTE risk-stratified prophylaxis has a positive impact in reducing inpatient and post-discharge VTE, it must be balanced against the risk of inpatient postoperative bleeding.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1169-1182, 2024.

Vascular Imaging in the Asymptomatic High-risk Cancer Population: A Role for Thrombosis Screening and Therapy Management

OBJECTIVES

We retrospectively examined the venous thromboembolism (VTE) events diagnosed in the Prophylaxis of High-Risk Ambulatory Cancer Patients Study (PHACS), a multi-center randomized trial, to assess the value of screening vascular imaging for the diagnosis of incidental VTE in high-risk cancer patients.

METHODS

A total of 117 asymptomatic cancer patients with a Khorana score ≥3 starting a new systemic chemotherapy regimen were enrolled in a prospective randomized control trial. Patients underwent baseline venous ultrasound (US) of the lower extremities (LEs) and screening contrast-enhanced chest computed tomography (CT). Those without preexisting VTE were then randomized into observation or dalteparin prophylaxis groups and were screened with serial US every 4 weeks for up to 12 weeks and imaged with contrast-enhanced chest CT at 12 weeks. Any additional imaging performed during the study period was also evaluated for VTE.

RESULTS

Baseline prevalence of incidental VTE was 9% (n = 10) with 58% percent of VTEs diagnosed by screening US. Incidence of VTE in the randomized phase of the trial was 16% (n = 16) with 21% (n = 10) of patients in the control arm and 12% (n = 6) of patients in the dalteparin arm developing VTE, a non-significant 9% absolute risk reduction (HR = 0.69, 95% CI 0.23-1.89). Sixty-nine percent of these patients were asymptomatic with 31% of patients diagnosed by screening US.

CONCLUSIONS

Adding screening US to routine oncologic surveillance CT in high-risk ambulatory cancer patients with a Khorana score ≥3 can lead to increased VTE detection, with potential for decreased morbidity, mortality, and health care spending.

Direct oral anticoagulants versus low molecular weight heparins for the treatment of cancer-associated thrombosis: a cost-effectiveness analysis

BACKGROUND

Recently, direct oral anticoagulants (DOACs) have been included in guidelines for the treatment of cancer-associated thrombosis (CAT) to be extended to suitable cancer patients. The purpose of this study was to compare the cost-effectiveness of using DOACs and low molecular weight heparins (LMWHs) for treating CAT from the perspective of the Chinese healthcare system.

METHODS

A Markov model was constructed to estimate the cost-effectiveness of the two strategies with a 6-month and 5-year time horizon. Input parameters were either sourced from the clinical trial, published literature. The primary outcome of the model was reported as incremental cost-effectiveness ratios (ICERs). Sensitivity analyses were performed to test model uncertainty.

RESULTS

The 6-month cost of DOACs was $ 654.65 with 0.40 quality adjusted life-years (QALYs) while the 6-month cost of LMWHs was $USD 1719.31 with 0.37 QALYs. Similarly, treatment with DOACs had a lower cost ($USD 657.85 vs. $USD 1716.56) and more health benefits (0.40 QALYs vs. 0.37 QALYs) than treatment with LMWHs in a subgroup of patients with gastrointestinal malignancy. We found treatment with DOACs would result in a large reduction in cost ($USD 1447.22 vs. $USD 3374.70) but a small reduction in QALYs (3.07 QALYs vs. 3.09 QALYs) compared with LMWHs over a 5-year time frame, resulting in an ICER of $USD 112895.50/QALYs. Sensitivity analysis confirmed the robustness of the results.

CONCLUSION

As compared to LMWHs, DOACs can be a cost-saving anticoagulant choice for the treatment of CAT in the general oncology population and gastrointestinal malignancy population.

Cost-Effectiveness of Different Strategies for the Prevention of Venous Thromboembolism After Total Hip Replacement in China

Introduction

The aim of this study was to evaluate the cost-effectiveness of rivaroxaban and apixaban versus enoxaparin for the universal prophylaxis of venous thromboembolism (VTE) and associated long-term complications in Chinese patients after total hip replacement (THR).

Methods

A decision model, which included both acute VTE (represented as a decision tree) and the long-term complications of VTE (represented as a Markov model), was developed to assess the economic outcomes of the three prophylactic strategies for Chinese patients after THR. Transition probabilities for acute VTE were derived from two randomized controlled studies, RECORD1 and ADVANCE3, of patients after THR. The transition probabilities of long-term complications after acute VTE, utilities, and costs were derived from the published literature and local healthcare settings. One-way and probabilistic sensitivity analyses (PSA) were performed to test the uncertainty concerning the model parameters. The quality-adjusted life years (QALYs) and direct medical costs were reported over a 5-year horizon, and incremental cost-effectiveness ratios (ICERs) were also calculated.

Results

Thromboprophylaxis with apixaban was estimated to have a higher cost (US $178.70) and more health benefits (0.0025 QALY) than thromboprophylaxis with enoxaparin over a 5-year time horizon, which resulted in an ICER of US $71,244 per QALY gained and was more than three times the GDP per capita of China in 2014 (US $22,140). Owing to the higher cost and lower generated QALYs, rivaroxaban was inferior to enoxaparin among post-THR patients. The sensitivity analyses confirmed these results.

Conclusions

The analysis found that apixaban was not cost-effective and that rivaroxaban was inferior to enoxaparin. This finding indicates that compared with enoxaparin, the use of apixaban for VTE prophylaxis after THR does not represent a good value for the cost at the acceptable threshold in China; in addition, the cost of rivaroxaban was higher with lower QALYs.

Pharmacoeconomic evaluation of dabigatran, rivaroxaban and apixaban versus enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement in Spain

BACKGROUND

Patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery are at high risk of developing venous thromboembolism (VTE). Thromboprophylaxis with low-molecular-weight heparin, such as enoxaparin, is standard of care in these patients. Recently, three direct oral anticoagulants (DOACs; dabigatran, rivaroxaban and apixaban), have been approved for this indication, but their cost effectiveness is still unclear as it has usually been extrapolated from surrogate venographic outcomes in clinical trials.

OBJECTIVE

To conduct a pharmacoeconomic evaluation of the DOACs versus subcutaneous (SC) enoxaparin for the prevention of VTE after THR or TKR surgery.

METHODS

A decision-tree model was developed using TreeAge Pro 2011 to compare the cost utility and cost effectiveness of the DOACs with SC enoxaparin, with separate models for THR and TKR over a 3-month postoperative time horizon from the perspective of the Spanish National Health System. The probabilities of events (symptomatic VTE, clinically relevant bleedings, heparin-induced thrombocytopenia and deaths) were derived from a systematic review and meta-analysis. We used local cost estimates (€2013) and utility values were obtained from the literature. We reported costs, quality-adjusted life-years (QALYs) and symptomatic VTE events. We conducted sensitivity analyses to evaluate parameter uncertainty.

RESULTS

The average costs per 1,000 patients treated with enoxaparin were higher than costs incurred by dabigatran, rivaroxaban and apixaban in THR (€435,208 vs. €283,574, €257,900 and €212,472, respectively) and TKR (€336,550 vs. €219,856, €251,734 and €201,946, respectively), with cost savings ranging from €151,634 to €222,766 in THR, and from €84,816 to €134,604 in TKR. Cost differences were largely driven by differences in costs associated with drug administration. The average QALYs per 1,000 patients treated were very similar for enoxaparin, dabigatran, rivaroxaban and apixaban in THR (199.34, 198.83, 199.08 and 199.68, respectively) and TKR (198.95, 199.41, 198.75 and 199.97, respectively). Rivaroxaban (in TKR and THR) and apixaban (in THR) avoided additional symptomatic VTE events compared with enoxaparin. Sensitivity analyses generally supported the robustness of the analysis to changes in model parameters.

CONCLUSIONS

Our model suggests, based on its underlying assumptions and data, that the DOACs are cost-saving alternatives to SC enoxaparin for the prevention of VTE after THR or TKR, in the Spanish healthcare setting.

Cost-effectiveness impact of rivaroxaban versus new and existing prophylaxis for the prevention of venous thromboembolism after total hip or knee replacement surgery in France, Italy and Spain

Venous thromboembolism (VTE) has a significant impact on healthcare costs but is largely preventable with anticoagulant prophylaxis using low-molecular-weight heparins (LMWHs), such as enoxaparin or dalteparin. Rivaroxaban and dabigatran etexilate are two new oral anticoagulants (NOACs) both compared with enoxaparin in separate trials. A decision analytic model with a healthcare and national payer perspective over a five-year time horizon was used to evaluate the cost-effectiveness of the NOACs for VTE prophylaxis after total hip replacement (THR) or total knee replacement (TKR) in France, Italy and Spain. Efficacy and safety data were obtained from randomised controlled trials of rivaroxaban vs enoxaparin and an indirect statistical comparison for rivaroxaban vs dabigatran. Rivaroxaban demonstrated dominance across all comparisons, indications and countries. In THR, total per-patient costs were reduced by up to €160 in the enoxaparin comparison and €115 in the dabigatran comparison, respectively. In addition, quality-adjusted life-years (QALYs) were increased by up to 0.0011 and 0.0012 in each comparison, respectively. Similarly, total costs were reduced in TKR by up to €137 and €28 in the enoxaparin and dabigatran comparisons, respectively. The total number of QALYs was increased by up to 0.0014 in the enoxaparin comparison and 0.0005 in the dabigatran comparison. The results were driven by costs since the incremental benefits were minimal. Rivaroxaban use could result in substantial healthcare cost savings and improved quality of life. The results are applicable across three European countries with differing healthcare systems so, potentially, could be generalised to a much wider population.

Pharmacoeconomic implications of thromboprophylaxis with new oral anticoagulants after total hip or knee replacement in the USA

INTRODUCTION

Adequate thromboprophylaxis after total hip or knee replacement (THR or TKR) is essential to reduce the incidence of venous thromboembolism (VTE) and its associated complications. Although effective, traditional anticoagulants are associated with a considerable economic burden, particularly when used outside the hospital setting. This article explores whether newer oral anticoagulants can reduce costs of VTE prophylaxis and therapy.

AREAS COVERED

Cost associated with vitamin K antagonists; indirect costs associated with complicated or inconvenient anticoagulation regimens, non-adherence and associated complications; potential of the newer oral anticoagulants, including direct thrombin inhibitors and direct factor Xa inhibitors, to produce indirect cost savings after THR or TKR through a potential reduction in VTE rates and administration and monitoring costs.

EXPERT OPINION

The use of new anticoagulants for VTE prophylaxis after THR or TKR can result in direct and indirect cost savings through improved efficacy by reducing VTE rates and decreased drug administration and monitoring costs compared with traditional anticoagulants. Future research will need to focus on cost analyses driven by clinical outcomes measured on the performance of these agents in actual clinical practice.

Long-term benefits of preventing venous thromboembolic events

BACKGROUND

Venous thromboembolism (VTE) and its long-term secondary complications are major health problems associated with high rates of morbidity and mortality and considerable costs for healthcare systems. Many patients receive suboptimal therapy, despite the availability of established and effective agents (including low molecular weight heparins, unfractionated heparin, fondaparinux and vitamin K antagonists) and evidence-based, internationally recognised guidelines. Limited knowledge of guidelines, concerns about bleeding risks and the inconvenience of parenteral administration and routine coagulation monitoring contribute to non-adherence to guidelines. Newer oral anticoagulants such as rivaroxaban, dabigatran etexilate, apixaban and edoxaban, which do not have the limitations of established anticoagulants, have been developed.

METHOD

Phase III randomised controlled trials for the treatment of acute VTE or for secondary prevention of recurrent VTE were identified in the PubMed and ClinicalTrials.gov databases. The search was limited to phase III studies and performed up to 26 March 2012 with the terms 'rivaroxaban OR Xarelto', 'dabigatran OR Pradaxa', 'apixaban OR Eliquis' and 'edoxaban OR DU-176b OR Lixiana'.

FINDINGS

A total of ten phase III studies, four published (three rivaroxaban, one dabigatran), three completed with results presented at recent congresses (dabigatran), and three ongoing (two apixaban, one edoxaban) were identified. Published and completed studies showed that rivaroxaban and dabigatran provided effective and convenient short-term treatment for deep vein thrombosis and VTE, respectively, when compared with standard of care, and showed superiority for long-term prevention of recurrent VTE when compared with placebo. Currently, rivaroxaban is the only newer anticoagulant that has been approved in Europe for the treatment of deep vein thrombosis and prevention of recurrent VTE.

CONCLUSIONS

Based on results of completed trials, rivaroxaban and dabigatran both may reduce the incidence of secondary complications of VTE and associated socioeconomic costs. Introduction of these newer anticoagulants is likely to have a substantial impact on clinical practice.

Relationship between deep vein thrombosis and pulmonary embolism following THA and TKA

Patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) are at risk for venous thromboembolisms, including deep vein thrombosis and pulmonary embolism. Most deep vein thromboses are asymptomatic, but they can lead to long-term morbidity to the same extent as symptomatic events. The risk of complications of venous thromboembolisms depends on the location of thrombi; potential long-term complications include recurrent venous thromboembolism, postthrombotic syndrome, and chronic thromboembolic pulmonary hypertension. Risk of recurrence persists for several years after the initial event. Approximately 20% of recurrent events are pulmonary embolisms, and approximately half of those are fatal. The causal relationship between deep vein thrombosis and pulmonary embolism remains controversial. Some consider them distinct clinical entities, while others have found asymptomatic distal deep vein thrombosis to be associated with elevated risk of developing pulmonary embolism. Unique coagulation factors may be associated with orthopedic surgery patients that differentiate them from patients undergoing other types of surgery. Symptomatic and asymptomatic deep vein thrombosis can lead to the development of recurrent venous thromboembolism, pulmonary embolism, postthrombotic syndrome, and chronic thromboembolic pulmonary hypertension, all of which are associated with reduced quality of life and increased health care expenditures. Thromboprophylaxis is therefore important in patients undergoing THA or TKA. However, traditional anticoagulants are not ideal, particularly for long-term use. Orthopedic surgeons should be aware of the causes and potential sequelae of venous thromboembolism and of the new thromboprophylactic agents that can help prevent it.

Cost effectiveness of rivaroxaban versus enoxaparin for prevention of post-surgical venous thromboembolism from a U.S. payer's perspective

BACKGROUND

Major orthopaedic surgery, such as total hip replacement (THR) and total knee replacement (TKR), is associated with an increased risk of venous thromboembolism (VTE).

OBJECTIVE

Clinical trials have demonstrated the efficacy of rivaroxaban, a once-daily, orally administered Factor Xa inhibitor, for the prevention of VTE in patients undergoing THR or TKR. This analysis evaluated the cost effectiveness of rivaroxaban compared with enoxaparin, from a U.S. payer's perspective.

METHODS

A decision-analytic model was developed to compare the costs and outcomes associated with rivaroxaban and enoxaparin for the prevention of VTE. The model replicated short-term clinical outcomes from the phase III RECORD trials. RECORD1 and RECORD2 compared rivaroxaban 10 mg daily (qd), given for 35 days, with enoxaparin 40 mg qd, given for 35 days or 10 to 14 days, respectively, in patients undergoing THR. RECORD3 compared 10 mg of rivaroxaban qd for 10 to 14 days versus 40 mg of enoxaparin qd for 10 to 14 days in patients undergoing TKR. The decision-analytic model also included data on long-term complications and sequelae as captured in observational studies and databases. It also included direct year 2010 medical costs over 1-year and 5-year time horizons. A series of sensitivity analyses were performed to determine the impact of different factors on the results of the model. Results of the cost-effectiveness analysis were reported in terms of symptomatic VTE events avoided.

RESULTS

Rivaroxaban was associated with cost savings of $US 511.93 per patient and prevented an average of 0.0145 symptomatic VTE events per patient in the THR population, compared with enoxaparin. For a TKR population, 10 to 14 days of rivaroxaban prophylaxis was associated with cost savings of $US 465.74 and prevented an average 0.0193 symptomatic VTE events per patient. Sensitivity analysis suggested that the results of the model were robust, with cost savings ranging from $US 133.96-629.57 in the THR population and $US 293.01-848.68 in the TKR population, depending on the variables used. Sensitivity analysis also suggested that the economic profile of rivaroxaban is improved when the time horizon of the model is extended from 1 year to 5 years. A probabilistic sensitivity analysis confirmed the findings of baseline results, showing that rivaroxaban was less costly and more effective in all model simulations for both populations.

CONCLUSIONS

This decision-analytic model analysis, from the U.S. payer's perspective, concluded that rivaroxaban may be cost saving in both the THR and the TKR populations, when compared with enoxaparin in the U.S.

In-hospital risk of venous thromboembolism and bleeding and associated costs for patients undergoing total hip or knee arthroplasty

OBJECTIVE

Benefits of anti-coagulation for venous thromboembolism (VTE) prevention in total hip and knee arthroplasty (THA/TKA) may be offset by increased risk of bleeding. The aim was to assess in-hospital risk of VTE and bleeding after THA/TKA and quantify any increased costs.

METHODS

Healthcare claims from the Premier Perspective(TM) Comparative Hospital Database (January 2000-September 2008) were selected for subjects ≥ 18 years with ≥ 1 diagnosis code for THA/TKA. VTE was defined as ≥ 1 code for deep vein thrombosis or pulmonary embolism. Bleeding was classified as major/non-major. Incremental in-hospital costs associated with VTE and bleeding were calculated as cost differences between inpatients with VTE or bleeding matched 1:1 with inpatients without VTE or bleeding.

RESULTS

A total of 820,197 inpatient stays were identified: 8042 had a VTE event and 7401 a bleeding event (2740 major bleeding). The risks of VTE, any bleeding, and major bleeding were 0.98, 0.90, and 0.33/100 inpatient stays, respectively. Mean incremental in-hospital costs per inpatient were $2663 for VTE, $2028 for bleeding, and $3198 for major bleeding.

LIMITATIONS

These included possible inaccuracies or omissions in procedures, diagnoses, or costs of claims data; no information on the amount of blood transfused or decreases in the hemoglobin level to evaluate bleeding event severity; and potential biases due to the observational design of the study.

CONCLUSIONS

In-hospital risk and incremental all-cause costs with THA/TKA were higher for VTE than for bleeding. Despite higher costs, major bleeding occurred less frequently than VTE, suggesting a favorable benefit/risk profile for VTE prophylaxis in THA/TKA.

Cost-effectiveness of rivaroxaban in the prevention of venous thromboembolism: A Canadian analysis using the Ontario Ministry of Health Perspective

OBJECTIVES

A cost-effectiveness model for rivaroxaban evaluated the cost-effectiveness of prophylaxis with rivaroxaban (a once-daily, orally administered Factor Xa inhibitor) vs enoxaparin in the prevention of venous thromboembolism (VTE) after total hip replacement (THR) and total knee replacement (TKR). This Canadian analysis was conducted using the Ontario Ministry of Health perspective over a 5-year time horizon. The model combined clinical data and builds upon existing economic models.

METHODS

The model included both acute VTE (represented as a decision tree) and long-term complications (represented as a Markov process with 1-year cycles) phases. The model allowed VTE event rates, quality-adjusted life expectancy and direct medical costs to be estimated over a 5-year time horizon, based on current approved practice patterns in Canada. A number of one-way sensitivity analyses were performed on the baseline assumptions, including a comparison of rivaroxaban with dalteparin, and probabilistic sensitivity analyses were performed to address any uncertainty concerning model inputs.

RESULTS

When comparing equal durations of therapy, rivaroxaban dominated enoxaparin in the prevention of VTE events in patients undergoing THR and TKR, providing more benefit at a lower cost. Rivaroxaban was cost-effective when comparing 35 days' prophylaxis with 14 days' prophylaxis with enoxaparin following THR. One-way and probabilistic sensitivity analyses demonstrated that the results of the economic analysis were robust to variations in key inputs. Rivaroxaban remained dominant during one-way sensitivity analyses comparing rivaroxaban with dalteparin after THR or TKR.

LIMITATIONS

Although clinical trial data were used in the prophylaxis module, assumptions and values used in the post-prophylaxis and long-term complication (LTC) modules were based on several different literature sources; it was not always possible to source Canadian data.

CONCLUSIONS

This economic analysis suggests that the use of rivaroxaban for the prophylaxis of VTE after THR or TKR in Canada was cost-effective.

Variation in physician deep vein thrombosis prophylaxis attitudes and practices at an academic tertiary care center

BACKGROUND

Deep vein thrombosis (DVT) remains a major cause of in-hospital morbidity and mortality. Effective DVT prophylaxis is available but underutilized. We sought to describe physician understanding of DVT epidemiology and prophylaxis practices.

METHODS

All medical and surgical residents, and hospitalist attendings were invited to participate in an on-line survey. Physicians were queried about DVT epidemiology, risk factors, prophylaxis practices, and complications. Means and standard deviations were calculated for ordinal responses. χ² was used for dichotomous variables.

RESULTS

Of 281 doctors emailed, 69/160 (43%) medical residents, 26/72 (36%) surgical residents, and 21/49 (43%) hospitalist attendings participated. All three overestimated DVT incidence and morbidity. Surgical residents listed paralysis as high risk and minor surgery as a low/no risk factor. Medical residents thought heart failure and varicose veins were low/no risk for developing DVT. Regarding prophylaxis, surgical residents did not identify ambulation as a prophylactic measure, and were more likely to use SCDs, compression stockings, and enoxaparin, while medical residents and hospitalist attendings prescribed unfractionated heparin most frequently. Medical residents reported that they would hold anticoagulants for comorbidities most frequently, but all 3 groups agreed that anticoagulant prophylaxis would not significantly increase bleeding risks.

CONCLUSIONS

Perceptions of DVT risk factors and prophylaxis practices vary by both physician specialty and attending/resident status. Prophylaxis practice differences may result from these perceptions.

Fondaparinux for isolated superficial vein thrombosis of the legs: a cost-effectiveness analysis

BACKGROUND

According to the Comparison of Arixtra in Lower Limb Superficial Vein Thrombosis with Placebo (CALISTO) study, a recent randomized, controlled trial, prophylactic fondaparinux can prevent thrombotic complications following superficial vein thrombosis (SVT). The cost-effectiveness of this treatment remains to be determined.

METHODS

We developed a decision-tree model comparing fondaparinux 2.5 mg daily for 45 days vs no treatment of SVT. It included all clinical events associated with SVT, its treatment, its complications, and all respective quality-adjustment factors. Data were mainly derived from the CALISTO study and the published literature. Measured outcomes comprised clinical events (VTE, major hemorrhage, death), quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs). The analysis was conducted using a lifetime time horizon from a health-care system perspective. We performed one-way and probabilistic sensitivity analyses to evaluate parameter uncertainty.

RESULTS

In 10,000 patients, we estimated that fondaparinux would prevent 123 VTE events and two deaths. On a per-patient basis, the incremental QALY compared with no treatment was 0.04 (1 day) at an incremental cost of $1,734, resulting in an ICER of $500,000 per QALY. This result remained robust in the one-way sensitivity analyses, with an ICER remaining > $100,000 per QALY throughout all ranges. Based on probabilistic sensitivity analyses, the probability that fondaparinux was cost-effective was 1% at a willingness-to-pay of $100,000 per QALY.

CONCLUSIONS

Fondaparinux for 45 days does not appear to be cost-effective when treating patients with isolated SVT of the legs. A better value for money could be obtained in subgroups of patients with a higher incidence of VTE after SVT. Shorter durations of treatment should be further evaluated in future clinical studies.

The AVAIL ME study: a multinational survey of VTE risk and prophylaxis

Venous thromboembolism (VTE) is a major public health issue that is frequently underestimated. The primary objective of this multinational survey was to identify patients at risk for VTE, and to define the rate of patients receiving appropriate prophylaxis in the Middle Eastern region. Standardized case report forms were filled by trained individuals on one predefined day in selected hospitals. Data were then entered and analyzed by independent biostatisticians. Risk was categorized according to American College of Chest Physicians (ACCP) guidelines, 2004. Logistic regressions were carried out to assess factors that determined VTE prophylaxis. 845 (37%) medical and 1421 (63%) surgical patients were eligible for the study. Patients were at low (4.2%), moderate (51.7%), high (9%) and very high risk (35.2%) for VTE. Any VTE prevention was given in 17.9, 41.7, 60.6 and 66.9% of respective risk categories, while ACCP guidelines were applied in 86.3, 41.1, 48.3 and 24.5% of these categories. Surgical patient type, immobility on admission, and contraceptive use were the most important drivers of VTE prophylaxis in those who were eligible to it (OR ≥ 2). Surgical patient type, immobility during hospitalization, existence of a VTE protocol and chronic heart failure were the most important drivers for VTE prophylaxis application in patients who were not eligible for it (OR ≥ 3). A concordance κ value of 0.16 was found between eligibility for VTE prophylaxis on one hand and its application in practice (P < 0.001). Risk factors for VTE and eligibility for VTE prophylaxis are common, but VTE prophylaxis and guidelines application are low.

Cost and outcomes associated with rivaroxaban vs enoxaparin for the prevention of postsurgical venous thromboembolism from a US payer's perspective

OBJECTIVE

The objective of this analysis was the evaluation of the outcomes and costs associated with rivaroxaban and enoxaparin for the prevention of postsurgical venous thromboembolism (VTE) in patients undergoing total hip replacement (THR) and total knee replacement (TKR) from the US payer perspective.

METHODS

VTE event rates have been reported in three Phase III clinical trials that compared rivaroxaban and enoxaparin for VTE prevention after orthopedic surgery during the prophylaxis (≤35 days for THR patients and 10-14 days for TKR patients) and post-prophylaxis periods (≤90 days following surgery). These data were used in this decision-analytic model to estimate and compare health outcomes and costs associated with rivaroxaban and enoxaparin. The base-case analysis considered the number and costs of symptomatic VTE events during the prophylaxis period only. A 90-day horizon was considered in the sensitivity analysis.

RESULTS

Following THR, when extended durations of prophylaxis (35 days) were compared, rivaroxaban was associated with lower costs than enoxaparin, with total saving costs of $695/patient. When an extended duration of rivaroxaban prophylaxis (35 days) was compared with a short duration (10-14 days) of enoxaparin prophylaxis, rivaroxaban was estimated to prevent 9.9 additional symptomatic VTE events per 1000 patients, while saving $244/patient (rate/1000 patients). In the TKR population, short duration of rivaroxaban prophylaxis was estimated to prevent 13.1 additional symptomatic VTE events per 1000 patients. It was also less costly than short duration enoxaparin prophylaxis, with a saving of $411/patient (rate/1000 patients).

LIMITATIONS

Only statistically significant differences were captured in the base-case economic analysis, and, therefore, differences in pulmonary embolism (PE) and bleeding events were not captured.

CONCLUSIONS

In this model, rivaroxaban reduced total treatment payer costs vs enoxaparin for the prevention of VTE in THR or TKR patients.

Simplifying thromboprophylaxis could improve outcomes in orthopaedic surgery

Venous thromboembolism is a serious complication after total hip or knee surgery, and there is a well-established clinical need for thromboprophylaxis. However, in a large number of cases adequate administration of thromboprophylaxis does not seem to occur after total joint arthroplasty. A major challenge in the management of thromboprophylaxis is to balance the benefits of treatment with the risks, including bleeding complications. Another potential barrier to the optimal use of thromboprophylaxis could be the inconvenience of currently available agents. Many surgeons therefore adopt a conservative approach towards thromboprophylaxis. Simplifying therapy with more convenient, efficacious, and safe anticoagulants could change attitudes to anticoagulant use and improve adherence to thromboprophylactic guidelines.

An Assessment of Surgical Thromboprophylaxis in a Tertiary Care Center

Background: Venous thromboembolism (VTE) is a frequent surgical complication. The American College of Chest Physicians (ACCP) recommends implementation of pharmacologic thromboprophylaxis according to surgery type and VTE risk factors. We conducted a retrospective cohort study of surgical admissions to determine the rate and predictors of use and appropriate use of thromboprophylaxis as defined by the 2004 ACCP guidelines and to determine the risk of postoperative VTE. Methods: Using data from an administrative health care database of the Centre Hospitalier Universitaire de Sherbrooke in the province of Quebec, we assembled a cohort of all consecutive surgical admissions in 2006 that met ACCP criteria for pharmacologic thromboprophylaxis and assessed rates of thromboprophylaxis presence and appropriateness. Multiple logistic regression was used to determine characteristics associated with thromboprophylaxis prescription. The incidence of postoperative VTE was assessed at 3 months. Results: Of 2286 surgical admissions that met criteria for pharmacologic thromboprophylaxis, 81% received thromboprophylaxis and, of these, 31% received appropriate thromboprophylaxis as per ACCP guidelines. Male sex, age below 40 years, and short-duration hospitalization were significantly associated with absent and inappropriate thromboprophylaxis. Cancer diagnosis and heart failure within 3 months preceding surgery were protective against inappropriate thromboprophylaxis (OR 0.43, 95% CI [0.33-0.57] and 0.43 [0.26-0.70], respectively). At 3 months following surgery, 27 patients (1.2%) developed VTE. Patients who developed VTE were more likely to have had a previous VTE than patients who did not develop a VTE ( P < .0001). Conclusions: Targeted recommendations, in particular concerning male patients with short duration hospitalization, may improve thromboprophylaxis compliance and appropriateness rates.

Avaliação da profilaxia do tromboembolismo venoso em hospital de grande porte

OBJETIVO: Avaliar a adequação da tromboprofilaxia em um hospital de grande porte em Vitória-ES, analisando possíveis preditores de aplicação de conduta inadequada. MÉTODOS: Trata-se de um estudo de corte transversal realizado através de análise de prontuários. Os pacientes analisados estiveram internados no hospital durante o ano de 2007, e tiveram seu risco de tromboembolismo venoso estratificado segundo a 8ª Diretriz para Profilaxia do TEV do American College of Chest Physicians (8º ACCP). A adequação da tromboprofilaxia foi determinada de acordo com a concordância entre a conduta instituída e a conduta preconizada nas diretrizes. Foram utilizados os softwares EpiInfo 3.4.3 e SPSS 13.0. RESULTADOS: Em 47% dos pacientes a tromboprofilaxia foi inadequada, sendo a não prescrição da medicação indicada o principal motivo (33%). Não houve diferença estatisticamente significante quando comparadas as taxas de inadequação da tromboprofilaxia entre pacientes clínicos e cirúrgicos, ou, entre pacientes internados em enfermaria e UTI. O número de fatores de risco para TEV foi inversamente proporcional à taxa de inadequação (p<0,05), assim como a faixa etária do paciente e a duração da internação (p<0,05). CONCLUSÃO: Os resultados obtidos apontam para níveis alarmantes de inadequação da tromboprofilaxia, o que evidencia a necessidade de programas de educação continuada no assunto para toda a equipe assistente.

Cost effectiveness of venous thromboembolism pharmacological prophylaxis in total hip and knee replacement: a systematic review

Total hip and knee replacements (THR and TKR) are high-risk settings for venous thromboembolism (VTE). This review summarizes the cost effectiveness of VTE prophylaxis regimens for THR and TKR. We searched MEDLINE (January 1997 to October 2009), EMBASE (January 1997 to June 2009) and the UK NHS Economic Evaluation Database (1997 to October 2009). We analysed recent cost-effectiveness studies examining five categories of comparisons: (i) anticoagulants (warfarin, low-molecular-weight heparin [LMWH] or fondaparinux) versus acetylsalicylic acid (aspirin); (ii) LMWH versus warfarin; (iii) fondaparinux versus LMWH; (iv) comparisons with new oral anticoagulants; and (v) extended-duration (> or =3 weeks) versus short-duration (<3 weeks) prophylaxis. We abstracted information on cost and effectiveness for each prophylaxis regimen in order to calculate an incremental cost-effectiveness ratio. Because of variations in effectiveness units reported and horizon length analysed, we calculated two cost-effectiveness ratios, one for the number of symptomatic VTE events avoided at 90 days and the other for QALYs at the 1-year mark or beyond. Our search identified 33 studies with 67 comparisons. After standardization, comparisons between LMWH and warfarin were inconclusive, whereas fondaparinux dominated LMWH in nearly every comparison. The latter results were derived from radiographic VTE rates. Extended-duration prophylaxis after THR was generally cost effective. Small numbers prohibit conclusions about aspirin, new oral anticoagulants or extended-duration prophylaxis after TKR. Fondaparinux after both THR and TKR and extended-duration LMWH after THR appear to be cost-effective prophylaxis regimens. Small numbers for other comparisons and absence of trials reporting symptomatic endpoints prohibit comprehensive conclusions.

A cost-effectiveness model comparing rivaroxaban and dabigatran etexilate with enoxaparin sodium as thromboprophylaxis after total hip and total knee replacement in the irish healthcare setting

BACKGROUND

It has been estimated that major orthopaedic surgery has the highest risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) when compared with other surgery. Two new orally active anticoagulants have recently become licensed in Ireland for the primary prevention of venous thromboembolism in adult patients undergoing elective total hip replacement (THR) or total knee replacement (TKR). Rivaroxaban (Xarelto) is a direct factor Xa inhibitor and dabigatran etexilate (Pradaxa) is a prodrug of the active compound dabigatran, which inhibits thrombin.

OBJECTIVE

To evaluate the cost effectiveness of rivaroxaban and dabigatran etexilate compared with enoxaparin sodium for the prophylaxis of venous thromboembolism in patients undergoing elective THR and TKR in the Irish healthcare setting.

METHODS

The evaluation was conducted from the Irish health-payer perspective. A static decision-tree model was developed with a 180-day post-surgery time horizon. Separate models for the disease states THR and TKR were run to accommodate the different venous thromboembolism risks associated with each procedure. Outcome measures were QALYs and life-years gained (LYG). Costs were valued in euro, year 2008 values. One-way sensitivity analysis of all probabilities in the model was performed. A probabilistic sensitivity analysis using second-order Monte Carlo simulation was performed to determine the probability of cost effectiveness at euro 45,000 per QALY threshold.

RESULTS

In the THR base-case model, rivaroxaban dominated both dabigatran etexilate and enoxaparin sodium. The incremental cost-effectiveness ratios for dabigatran etexilate relative to enoxaparin were euro 23,934 per LYG and euro 17,835 per QALY. In the TKR base-case model, rivaroxaban dominated both dabigatran etexilate and enoxaparin sodium. Dabigatran etexilate also dominated enoxaparin sodium. In the one-way sensitivity analysis, the THR model was robust to all but four probability variations; the TKR model was robust to all variations. At a cost-effectiveness threshold of euro 45,000 per QALY, the probability that rivaroxaban was the most cost-effective strategy after THR was 39%, followed by dabigatran etexilate at 32% and enoxaparin sodium at 29%. The probability that rivaroxaban was the most cost-effective strategy after TKR was 46%, followed by dabigatran etexilate at 30% and enoxaparin sodium at 24%.

CONCLUSION

Base-case analysis indicates that when both rivaroxaban and dabigatran etexilate are compared with enoxaparin sodium, rivaroxaban is the less costly and more effective option after THR and TKR. Probabilistic sensitivity analysis indicates that rivaroxaban is the most cost-effective strategy at a cost-effectiveness threshold of euro 45,000 per QALY; however, there is uncertainty regarding this strategy being more cost effective than dabigatran etexilate when both are compared with enoxaparin sodium.

Cost-effectiveness of venous thromboembolism prophylaxis in total hip and knee replacement surgery: the evolving application of health economic modelling over 20 years

OBJECTIVES

In the last two decades, there has been considerable evolution of methods for cost-effectiveness modelling. Some of the first models were developed in the area of venous thromboembolism (VTE) prophylaxis. Hence, this area can serve as an important example to illustrate evolving standards. Our objectives are to document evolving methodology by describing VTE models, assess their critical strengths and weaknesses, and inform future advances for models in this therapeutic area.

RESEARCH DESIGN AND METHODS

A systematic review of economic models of primary VTE prevention following hip and knee replacement surgery was undertaken. Electronic searches of PubMed, EMBASE, the Cochrane library, and grey literature were conducted (1985-2006). Reference lists of included articles and reviews were examined for relevant studies.

RESULTS

Twenty-nine cost-effectiveness models were identified. Nineteen other cost-effectiveness analyses were excluded because they were not model-based; 16 were simple cost calculations and three were analyses of resource use data collected alongside clinical trials. The majority of models (24) were constructed as decision trees, frequently utilising previously published model structures, with some adaptation for new comparators, and/or addition of relevant events omitted by earlier models (e.g., bleeding due to prophylactic treatment). Later models have included Markov processes to model potential long-term consequences of VTE (recurrent VTE and post-thrombotic syndrome) over longer time horizons. Systematic identification of clinical evidence and more sophisticated analysis methods (e.g., Bayesian mixed-treatment comparisons and probabilistic sensitivity analyses) have recently been introduced.

CONCLUSIONS

Model structures have evolved substantially in this highly studied therapeutic area, with improvements made to the model structure, the comprehensiveness of clinical evidence included, and the underlying calculation methodology.

Risk-based evaluation of thromboprophylaxis among surgical inpatients: are low risk patients treated unnecessarily?

BACKGROUND

Venous thromboembolism is a common source of morbidity and mortality but a variety of preventative measures are available.

AIMS

To audit the current practice of thromboprophylaxis and compare against published protocols.

METHODS

Three-hundred and seventy-six (376) surgical patients were surveyed prospectively. A Performa was completed recording the presence of up to 11 risk factors. A risk score was calculated and the use of specific thromboprophylatic measures identified.

RESULTS

Heparin thromboprophylaxis was widely used, eight patients (who were on aspirin therapy) failed to receive any prophylaxis (risk factors 4-6). In addition there were 60 patients at low risk (risk score <2) received LMWH from which they were unlikely to benefit.

CONCLUSIONS

Thromboembolic prophylaxis is widely but unselectively applied. Adoption of a risk: benefit ratio approach should ensure those who would benefit from thromboprophylaxis are adequately treated while those in whom thromboprophylaxis is not indicated are spared unnecessary therapy.

Estimated annual costs of prophylaxis and treatment of venous thromboembolic events associated with major orthopedic surgery in France

Venous Thromboembolism (VTE) remains a major complication following orthopedic surgery despite heparin prophylaxis. Clinical consequences associated with this complication are deep vein thrombosis (DVT), pulmonary embolism, and long-term consequences of DVT, especially Postthrombotic syndrome (PTS). The purpose of the present study was to estimate the annual direct costs of VTE following major orthopedic surgery of the lower limb in France. This cost of illness study was performed by using available information from health system databases (1999) and literature and specific surveys (2002). Direct costs were calculated by using estimates of the number of patients with major orthopedic surgery in France during one year. Patients presenting with VTE were identified from the national disease-related group inpatient database. Additional resource consumption was identified by comparison with disease-related groups without the VTE complications. Ambulatory care costs after hospitalization, for recurrences and PTS, were estimated from specific surveys of general practitioners and venous disease specialists. Total annual costs of VTE associated with major orthopedic surgery for the French Sickness Fund were estimated to be approximately 60 million euros over 1 year with 28 million euros for inpatient care and 30 million euros for recurrences and PTS.

A study on the safety, efficacy, and efficiency of sulodexide compared with acenocoumarol in secondary prophylaxis in patients with deep venous thrombosis

This study was carried out to study the safety and efficacy of a fixed dosage of sulodexide compared to adjusted dosages (INR) of acenocoumarol as secondary prophylaxis in patients with deep vein thrombosis (DVT) in lower limbs. An economic evaluation based on the criteria of use in normal clinical practice was also performed. One hundred and fifty patients of both sexes were included, all over 18 years of age and diagnosed with proximal DVT of the lower limbs by color echo-Doppler, and with clinical evolution of less than 1 month. The patients were initially treated with low-molecular-weight heparin (LMWH) and urokinase in accordance with the established protocol. They were then randomized to continue treatment with acenocoumarol and INR adjustments every 30 days, or with sulodexide. Treatment was extended for 3 months with monthly follow-up visits and a final visit at 3 months posttreatment. No differences between the groups were detected concerning demographic or basal characteristics in clinical evolution or adverse reactions. In the group treated with sulodexide, no major/minor hemorrhagic complications were detected. On the other hand, in the acenocoumarol group, 1 major hemorrhage and 9 minor hemorrhages were produced (13.3%), reaching statistical difference in relation to the sulodexide group (p = 0.014; CI from 95% of 4.7% to 19.4%). Regarding the economic impact, treatment costs with sulodexide are much less than those with acenocoumarol, the data confirmed by the sensitivity analyses performed. The results prove the efficacy, safety, and efficiency of sulodexide as a secondary prophylaxis in thromboembolic disease, avoiding hemorrhagic risks and the monitoring of patients, and providing significant savings to the health system.

Cost-effectiveness of fondaparinux compared with enoxaparin as prophylaxis against venous thromboembolism in patients undergoing hip fracture surgery

OBJECTIVE

To evaluate the cost-effectiveness of fondaparinux relative to enoxaparin as prophylaxis against venous thromboembolism (VTE) in patients undergoing hip fracture surgery.

METHODS

A decision analysis model was created to simulate the impact of fondaparinux 2.5 mg once daily relative to enoxaparin 30 mg twice daily on patient outcomes and costs over various time points up to 5 years after surgery. Probabilities for the analysis were estimated for a hypothetical cohort of 1000 patients undergoing hip fracture surgery in the United States receiving either fondaparinux or enoxaparin according to comparative trial results. Resource use and costs (2003 dollars) were obtained from large health-care databases. Outcome measures were rates of symptomatic VTE events, health-care costs, and incremental cost-effectiveness ratios.

RESULTS

Fondaparinux is estimated to prevent an additional 30 VTE events (per 1000 patients) at 3 months compared with enoxaparin, producing savings of 103 dollars at discharge, 290 dollars over 1 month, 361 dollars over 3 months, and 466 dollars over 5 years. The results remain robust to clinically plausible variation in input parameters and assumptions.

CONCLUSIONS

Fondaparinux improves outcomes and is cost-saving over a broad range of assumptions compared with enoxaparin for prophylaxis of VTE after hip fracture surgery.

The Post-thrombotic Syndrome: The Forgotten Morbidity of Deep Venous Thrombosis

The postthrombotic syndrome (PTS) is the most common complication of deep venous thrombosis (DVT) yet has received little attention from clinicians and researchers. Clinically, PTS is characterized by chronic pain, swelling, heaviness and other signs in the affected limb. In severe cases, venous ulcers may develop. PTS is burdensome and costly to patients and society because of its high prevalence, severity and chronicity. Preventing DVT with the use of effective thromboprophylaxis in high-risk patients and settings and minimizing the risk of ipsilateral DVT recurrence are likely to reduce the frequency of PTS. Compression stockings worn daily after DVT appear to reduce the incidence and severity of PTS but questions regarding their use and effectiveness remain. Future research should focus on identifying patients at high risk for PTS, assessing the role of thrombolysis in preventing PTS and evaluating the optimal use of compression stockings in preventing and treating PTS. In addition, new therapies to treat PTS should be sought and evaluated.

Pharmacoeconomic analysis of fondaparinux versus enoxaparin for the prevention of thromboembolic events in orthopedic surgery patients

INTRODUCTION

Fondaparinux is a novel synthetic antithrombotic that has been evaluated for the prevention of venous thromboembolism (VTE). In four large trials in patients who underwent major hip or knee surgery, fondaparinux was found to have a good safety profile and be more effective than enoxaparin. To generate Canadian pharmacoeconomic data for fondaparinux, an internationally developed cohort deterministic model was used to estimate the costs and consequences of prophylaxis with fondaparinux compared with enoxaparin in the Canadian orthopedic surgical setting.

DESIGN AND SETTING

A health economic advisory group was assembled to guide the pharmacoeconomic evaluation. Efficacy and safety data for fondaparinux relative to enoxaparin were abstracted from a meta-analysis of four randomized trials. Canadian cost data to populate the model were obtained from a resource-use survey of four large Canadian hospitals, from the Canadian Institute for Health Information (CIHI), and from the Canadian economic literature. Case-mix information obtained from CIHI was incorporated into the cohort deterministic model, which predicted the number of VTEs and bleeds following prophylaxis with fondaparinux or enoxaparin within 90 days of surgery, and the associated overall cost difference. The stability of the base-case findings was evaluated with sensitivity analyses.

STUDY PERSPECTIVE

Canadian healthcare system perspective.

MAIN OUTCOME MEASURES AND RESULTS

Assuming a case mix of 50,693 major hip or knee surgeries performed in Canada in 1999/2000 (as reported by CIHI), the model predicted that prophylaxis with fondaparinux would avoid an additional 16 symptomatic VTEs per 1000 patients over the first 90 days, with an average cost savings of Can 55 dollars per patient. These findings were stable when key economic and clinical parameters were varied, including bleeding events.

CONCLUSIONS

Our results suggest that in Canada, prophylactic fondaparinux compared with enoxaparin avoids VTEs and is associated with lower costs in patients who undergo major hip or knee surgery.

Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This article discusses the prevention of venous thromboembolism (VTE) and is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following. We recommend against the use of aspirin alone as thromboprophylaxis for any patient group (Grade 1A). For moderate-risk general surgery patients, we recommend prophylaxis with low-dose unfractionated heparin (LDUH) (5,000 U bid) or low-molecular-weight heparin (LMWH) [< or = 3,400 U once daily] (both Grade 1A). For higher risk general surgery patients, we recommend thromboprophylaxis with LDUH (5,000 U tid) or LMWH (> 3,400 U daily) [both Grade 1A]. For high-risk general surgery patients with multiple risk factors, we recommend combining pharmacologic methods (LDUH three times daily or LMWH, > 3,400 U daily) with the use of graduated compression stockings and/or intermittent pneumatic compression devices (Grade 1C+). We recommend that thromboprophylaxis be used in all patients undergoing major gynecologic surgery (Grade 1A) or major, open urologic procedures, and we recommend prophylaxis with LDUH two times or three times daily (Grade 1A). For patients undergoing elective total hip or knee arthroplasty, we recommend one of the following three anticoagulant agents: LMWH, fondaparinux, or adjusted-dose vitamin K antagonist (VKA) [international normalized ratio (INR) target, 2.5; range, 2.0 to 3.0] (all Grade 1A). For patients undergoing hip fracture surgery (HFS), we recommend the routine use of fondaparinux (Grade 1A), LMWH (Grade 1C+), VKA (target INR, 2.5; range, 2.0 to 3.0) [Grade 2B], or LDUH (Grade 1B). We recommend that patients undergoing hip or knee arthroplasty, or HFS receive thromboprophylaxis for at least 10 days (Grade 1A). We recommend that all trauma patients with at least one risk factor for VTE receive thromboprophylaxis (Grade 1A). In acutely ill medical patients who have been admitted to the hospital with congestive heart failure or severe respiratory disease, or who are confined to bed and have one or more additional risk factors, we recommend prophylaxis with LDUH (Grade 1A) or LMWH (Grade 1A). We recommend, on admission to the intensive care unit, all patients be assessed for their risk of VTE. Accordingly, most patients should receive thromboprophylaxis (Grade 1A).

Pharmacoeconomics of Thrombosis Management

Venous thromboembolism (VTE) is the cause of significant morbidity and mortality and may lead to other complications, including recurrent VTE and long-term postthrombotic syndrome. Venous thromboembolism represents a huge health economic burden of nearly 500 million dollars/year in the United States. Without adequate prophylaxis, patients undergoing major orthopedic surgery are at high risk of developing VTE. Prophylaxis with either unfractionated heparin or warfarin not only substantially reduces the risk of VTE after orthopedic surgery, but also is more cost-effective than no prophylaxis. Low-molecular-weight heparins (LMWHs) have been shown to be superior to unfractionated heparin or warfarin, and despite the fact that they are more expensive, they are cost-effective. Large-scale clinical trials have shown that fondaparinux further reduces the likelihood of VTE complications after major orthopedic surgery. A review of the pharmacoeconomic evaluations of fondaparinux leads to the conclusion that fondaparinux is a cost-effective alternative to LMWHs in VTE prophylaxis.

A cost-effectiveness analysis of fondaparinux sodium compared with enoxaparin sodium as prophylaxis against venous thromboembolism: use in patients undergoing major orthopaedic surgery

OBJECTIVE

To determine the cost effectiveness of fondaparinux sodium compared with enoxaparin sodium for prophylaxis against venous thromboembolism in patients undergoing major orthopaedic surgery.

METHODS

Using a cohort simulation model, two primary analyses were conducted from the perspective of the US healthcare payer. Probabilities for a trial-based analysis were obtained from patients participating in the fondaparinux clinical trial programme supplemented with data from published literature. Probabilities for a label-based analysis were estimated for a hypothetical cohort of US patients receiving either fondaparinux or enoxaparin as recommended by US FDA-approved labelling. Resource use and costs were obtained from large US healthcare databases. Outcome measures were rates of symptomatic thromboembolic events and healthcare costs. Costs were in 2003 values.

RESULTS

In the trial-based analysis, fondaparinux was estimated to prevent 15.1 symptomatic venous thromboembolic events (per 1,000 patients) at 3 months for patients undergoing major orthopaedic surgery compared with enoxaparin. The cost savings (per patient) of using fondaparinux over enoxaparin are US 61 dollars at 30 days, US 89 dollars at 3 months, and US 155 dollars at 5 years. In the label-based analysis, fondaparinux was estimated to prevent 17.8 venous thromboembolic events (per 1,000 patients) at 3 months compared with enoxaparin, producing savings per patient of US 25 dollars at discharge, US 112 dollars over 1 month, US 141 dollars over 3 months and US 234 dollars over 5 years. Results remain robust to clinically plausible variation in input parameters and assumptions.

CONCLUSION

Our model suggests that fondaparinux, when compared with the current standard regimen of enoxaparin for prophylaxis of venous thromboembolism in major orthopaedic surgery, improves outcomes and is cost saving from a US healthcare-payer perspective over the broad range of assumptions evaluated.